Investigation of the mechanisms by which hot isostatic pressing improves the fatigue performance of powder bed fused Ti-6Al-4V
Investigation of the mechanisms by which hot isostatic pressing improves the fatigue performance of powder bed fused Ti-6Al-4V
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DOI：
10.1016/j.ijfatigue.2018.10.015
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发表时间：
2019-03-01
影响因子：
6
通讯作者：
Phan, N.
中科院分区：
文献类型：
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作者：
Li, P.;Warner, D. H.;Phan, N.
为了获得具有良好疲劳性能的粉末床层熔(PBF)Ti-6Al-4V零件，经常需要热等静压(HIP)。这篇手稿试图阐明髋关节治疗改善高周疲劳性能的机制。考虑了几种机制，并对照文献中可用的实验数据集进行了检查。研究结果表明，热等静压可以通过降低缺陷尺寸低于阈值和改变缺陷周围的微观结构来减少可能引发疲劳裂纹的缺陷群体的比例，从而起到最显著的作用。考虑到后一个结论的新颖性，进行了电子背散射衍射显微镜研究以进行验证。所获得的认识为选择最佳的热等温参数(温度-压力-时间)以保证PBF钛合金的高周疲劳性能提供了初步的指导。
Hot isostatic pressing (HIP) is often needed to obtain powder bed fused (PBF) Ti-6Al-4V parts with good fatigue performance. This manuscript attempts to clarify the mechanisms through which HIP treatment acts to improve high cycle fatigue performance. Several mechanisms are considered and examined against experimental data sets available in the literature. The results suggest that HIP may act most significantly by decreasing the fraction of the defect population that can initiate fatigue cracks, both by decreasing defect sizes below a threshold and by changing the microstructure that surrounds defects. Given the novelty of the latter conclusion, an electron backscatter diffraction microscopy study was performed for validation. The gained understanding provides initial guidance on the choice of optimum HIP soak parameters (Temperature-Pressure-Time) for the high cycle fatigue performance of PBF Ti-6Al-4V.